An analysis of the neural mechanisms involved in the synchrony of female sexual behavior to the release of pituitary luteninizing hormone (LH) will be conducted, emphasizing the role of Prostaglandin E2 (PGE2) in the stimulation of LH-releasing hormone (LHRH). Intracranial administration of PGE2 to female rats will be used to localize the neural site of action of PGE2 in sexual behavior and LH release. Radioimmunoassay of PGE2 and LHRH concentratons in different brain regions will be performed to assess the effects of vaginal stimulation, steroid treatment, or hypoohysectomy. The concentrations of PGE2 and the LHRH will be correlated to the behavioral and gonadotropin effects of the different treatments. The results will yield a possible mechanism of action of steroids and external stimulation that uses PGE2 as a signal for the synchrony of sexual behavior and pituitary function.